Key:
Ball by door = ball 1
Ball near switch = ball 2
Ball by column = ball 3

Ball 3 => NW to Ice block
Ball 1 => SE to column
Ball 3 => NE to Ball 2
Destroy NE Ice block (in front of Balls 3&2)
Balls 3&2 => NE to wall
Ball 1 => SW to other column
Ball 1 => NW to ice block
Ball 1 => NE to Balls 3&2
Ball 1 => NW to switch